1. Field of the Invention
This invention relates to a semiconductor device having a DRAM or the like, and particularly to a semiconductor device formed by stacking a plurality of chip dies.
2. Description of the Related Art
An example of this type of semiconductor devices is a semiconductor device in which a memory module is formed by stacking a plurality of DRAM chips on an IO chip mounted on an interposer board and connecting the DRAM chips to the IO chip by means of through electrodes formed within through silicon vias (Sivia) (see Japanese Laid-Open Patent Publication No. 2004-327474 (Patent Document 1) corresponding to U.S. Pat. No. 7,123,497 (Patent Document 2).
More specifically, according to Patent Document 1, each of the DRAM chips of the memory module has a plurality of vias and through electrodes formed within these vias in order to transfer data signals and data mask signals accompanied by the data signals.
A semiconductor device configured in this manner has advantages that the length of wiring lines connecting a plurality of DRAM chips can be shortened and a DLL, consuming a large amount of current, need be provided only on an IO chip.